UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
246 Views
Registered: ‎10-01-2019

ZCU106 VCU_TRD v2018.3 - Minimum achievable target-bitrate for omxhenc and max-bitrate for udpsink

Jump to solution

Hi All,

I have two (related) questions based on the pipeline below:

gst-launch-1.0 --eos-on-shutdown v4l2src device=/dev/video0 io-mode=4 ! capsfilter caps="video/x-raw, width=1920, height=1080, format=NV12,framerate=60/1" ! videorate max-rate=15 ! tee name=t ! queue ! kmssink bus-id=a0070000.v_mix t. ! queue ! omxh264enc gop-length=60 gop-mode=0 low-bandwidth=FALSE target-bitrate=600 num-slices=8 control-rate=2 qp-mode=2 periodicity-idr=60 prefetch-buffer=TRUE latency-mode=1 b-frames=0 filler-data=TRUE ! capsfilter caps="video/x-h264, profile=high" ! queue ! mpegtsmux alignment=7 ! rtpmp2tpay pt=33 ! queue ! udpsink host=192.168.2.200 async=FALSE send-duplicates=FALSE max-bitrate=1500000 port=5004 qos-dscp=60

Question 1:

What is the minimum value of target-bitrate that can be achieved by the omxh encoders? When using a slightly modified version of the pipeline (where I compress and decompress the video before displaying), I have noticed that usable video is still obtained on the display even with very low target-bitrate say 1kbps. I am yet to confirm using gstshark but I'm almost certain the encoder outputs some other bitrate (and not 1kbps) when set to 1kbps. Assuming my assumption is true, how can one force the encoder to try and achieve the specified target-bitrate?

 

Question 2 :

What's is the recommended ratio encoder target-bitrate : udp stream max-bitrate. The quality of the video on the receiver is affected by changes in this ratio e.g. changing the above pipeline to target-bitrate=800 results in glitches/discontinuities in the video on the stream receiver side.

Thanks in advance

Tags (2)
0 Kudos
1 Solution

Accepted Solutions
Scholar watari
Scholar
150 Views
Registered: ‎06-16-2013

Re: ZCU106 VCU_TRD v2018.3 - Minimum achievable target-bitrate for omxhenc and max-bitrate for udpsink

Jump to solution

Hi @joshua_tatenda 

 

Here is my opinion.

Would you refer them ?

 

Q1)

It depends on input video stream.

For example, static video stream like CG, it can reduce encoded size.

 

Q2)

Since udpsink is executed by CPU and it is affected by CPU resource, bus utilization, quality of network driver, network buffer size on linux kernel and so on.

So, I'm propably sure that it it hard to correctly answer it.

 

Best regards,

View solution in original post

1 Reply
Scholar watari
Scholar
151 Views
Registered: ‎06-16-2013

Re: ZCU106 VCU_TRD v2018.3 - Minimum achievable target-bitrate for omxhenc and max-bitrate for udpsink

Jump to solution

Hi @joshua_tatenda 

 

Here is my opinion.

Would you refer them ?

 

Q1)

It depends on input video stream.

For example, static video stream like CG, it can reduce encoded size.

 

Q2)

Since udpsink is executed by CPU and it is affected by CPU resource, bus utilization, quality of network driver, network buffer size on linux kernel and so on.

So, I'm propably sure that it it hard to correctly answer it.

 

Best regards,

View solution in original post